1. Technical Field
The present invention relates to a liquid container and a method of manufacturing the liquid container, which supplies a predetermined liquid to a liquid consuming apparatus such as a liquid ejecting head or the like for ejecting a small amount of liquid droplets.
2. Related Art
When a liquid ejecting head of a printing apparatus, a microprocessor, or a commercial ink jet printing apparatus, which is used when a high quality printing is necessary, is operated in a state where a ejection liquid is supplied from a liquid container, but the liquid is not supplied to the liquid ejecting head, a so-called idle printing may occur, thereby damaging the liquid ejecting head. Accordingly, in order to prevent the idle printing, an amount of liquid remained in the liquid container has to be monitored.
In the printing apparatus, there have been proposed various methods of mounting a residual liquid quantity detecting unit for detecting an amount of residual ink in an ink cartridge, which is the liquid container for containing ink.
The ink cartridge mounted in the printing apparatus can be broadly classified into an air-open ink cartridge and an airtight ink cartridge.
In the air-open ink cartridge, an air introducing hole communicates with an ink container partitioned in the ink cartridge. In addition, since air pressure can be used to supply ink from the ink cartridge to the printing apparatus by introducing open air into the ink container with consumption of ink contained in the ink container, the configuration of the liquid container can be simplified. As a result, the ink air-open ink cartridge is suitable for a relatively small ink cartridge.
Alternatively, in the airtight ink cartridge, the ink cartridge is formed of a flexible bag having an airtight structure or the like, and thus degradation of ink occurring due to contact of open air can be prevented. Since quality of the contained ink can be reliably maintained for a long time, the airtight ink cartridge is suitable for a large-capacity ink cartridge. However, a pressing mechanism for pressing the flexible bag, which is the ink containing portion, from the outside may be provided. Accordingly, the size of the ink cartridge and the printing apparatus can be easily increased, compared with the air-open ink cartridge.
In a case where the residual liquid quantity detecting unit is provided with the ink cartridge, a problem arises in that the residual liquid quantity detecting unit has to be attached to a case (a container body) of the ink cartridge from the viewpoint of simplicity of a manufacturing process of the ink cartridge and improvement in productivity.
Presently, as the air-open ink cartridge capable of easily attaching the residual liquid quantity detecting unit to the case, there has been proposed an ink cartridge in which an attachment hole formed through the container body having the ink containing portion to communicate with the ink containing portion is formed and the residual liquid quantity detecting unit is rotated to be inserted into the attachment hole.
In this case, the residual liquid quantity detecting unit includes a cylindrical portion that is rotated to be fitted to the attachment hole, a locking piece that protrudes toward the outside of a radius direction from the outer circumferential surface of the cylindrical portion and is engaged in a locking portion provided in the container body to be fixed on the container body by rotation of the cylindrical portion, and a piezoelectric unit is laid in the cylindrical portion. The residual liquid quantity detecting unit is adapted to detect an amount of ink remaining in the ink container on the basis of residual vibration oscillated in the ink container by the piezoelectric unit.
In such an ink cartridge, the residual liquid quantity detecting unit is attached to the container body in a manner that the residual liquid quantity detecting unit is rotated to be inserted into the attachment hole formed on the container body, and thus the process of manufacturing the ink cartridge can be simplified to improve the productivity.
Patent Document 1: JP-A-2001-328280
However, in the case of the airtight ink cartridge, the above-described method of rotating the residual liquid quantity detecting unit to be inserted, which is used in the air-open ink cartridge, cannot be used.
In the case of the air-open ink cartridge, open air is introduced into an ink containing chamber with consumption of ink. Accordingly, since a vibration characteristic in the ink containing chamber considerably varies in accordance with the consumption of the ink, a piezoelectric unit can contribute to detect an amount of remaining ink with high precision by simply measuring residual vibration. As a result, it is also possible to make the piezoelectric unit compact.
In contrast, in the case of the airtight ink cartridge, even though ink is consumed, open air is not introduced into the ink containing chamber. Consequently, the amount of remaining ink cannot be measured with high precision by simply measuring the residual vibration in the air-open ink cartridge. For this reason, as a residual liquid quantity detecting unit, there has been proposed a unit that measures varying pressure (mass flow) in accordance with the amount of remaining ink. However, even in this case, since a flow passage for allowing the remaining ink to flow and a sensor for detecting variation in the ink flowing into the flow passage have to be provided, a problem arises in that the size of a residual liquid quantity detecting unit becomes larger.